Palynological evidence for Neogene climatic change in Hungary

Átírás

1 Ocassional Papers of the Geological Institute of Hungary, volume 205 Palynological evidence for Neogene climatic change in Hungary ESZTER NAGY Geological Institute of Hungary, 2005

2 A Magyar Állami Földtani Intézet 205. Alkalmi kiadványa Vol. 205 of the Occassional Papers of the Geological Institute of Hungary Copyright Magyar Állami Földtani intézet (Geological Institute of Hungary), 2005 Minden jog fenntartva All rights reserved! Sponsors: Országos Tudományos Kutatási Alap Hungarian National Science Foundation Magyar Tudományos Akadémia VIII. Biológiai Tudományok Osztálya, X. Földtudományok Osztálya Hungarian Academy of Sciences VIII. Section of Biological Sciences X. Section of Earth Sciences Reviewers: GÉZA HÁMOR ENIKŐ MAGYARI Translator: MIKLÓS KÁZMÉR Technical Editors: OLGA PIROS, DEZSŐ SIMONYI DTP: OLGA PIROS Cover design: ZOLTÁN TÓTH Kiadja a Magyar Állami Földtani Intézet Published by the Geological Institute of Hungary Responsible editor: KÁROLY BREZSNYÁNSZKY Director ISBN

3 Contents Tartalom Introduction Methods Palaeoclimatic interpretation Early Miocene Egerian Eggenburgian Ottnangian Middle Miocene Karpatian Badenian (Lower and Middle Badenian) Upper Miocene Upper Badenian Sarmatian Pannonian (sensu PAPP 1985) Pontian (sensu STEVANOVIĆ 1990) Pliocene Palaeoclimatological summary Early Miocene Egerian Early Egerian climate Late Egerian climate Eggenburgian climate Ottnangian climate Early Miocene climate Middle Miocene Karpatian climate Early Middle Badenian climate Middle Miocene climate Late Miocene Late Badenian climate Sarmatian climate Pannonian climate

4 Pontian climate Late Miocene climate Pliocene (Dacian) climate The Miocene climatic curve *** A magyarországi neogén éghajlati adatai palinológiai kutatások alapján A téma kialakulásának körülményei A kutatás módja Értékelés Alsó-miocén Egri Eggenburgi Ottnangi Középső-miocén Kárpáti Badeni (alsó- és középső-badeni) Felső-miocén Felső-badeni Szarmata Pannóniai (sensu PAPP 1985) Pontusi (sensu STEVANOVIĆ 1990) Pliocén Összefoglaló értékelés Kora-miocén Egri A kora-egri éghajlata A késő-egri éghajlata Az eggenburgi éghajlata Az ottnangi éghajlata A kora-miocén éghajlata Középső-miocén A kárpáti éghajlata A kora- és középső-badeni éghajlata A középső-miocén éghajlata Késő-miocén A késő-badeni éghajlata A szarmata éghajlata A pannóniai éghajlata A pontusi éghajlata A késő-miocén éghajlata A pliocén dáciai emelet éghajlata A miocén éghajlati görbe Irodalom References

5 Introduction Palynological research offers significant data for palaeoclimatological interpretation. Deep appreciation of the morphology of modern pollen grains and their comparison with fossil counterparts of various ages offer a solid basis for recognition of their relationship, allowing to draw conclusions on past climates. During a lifetime of palaeopalynological research the author always cared to know both fossil and related Recent floras. Besides learning from handbooks (BERTSCH 1942; ERDTMAN 1943, 1952, 1957, etc), I persistently made attemps to study herbaria, botanical gardens, and the vegetation itself under warmer climates. Necessarily, only limited opportunities were available for the latter. Fortunately, my initial studies concerned Quaternary pollen floras, along with the Recent local flora. As my studies progressed towards the Neogene, I approached terra incognita: there was no previous description available on the palynoflora of the Pannonian Basin. Besides routine work mostly on borehole sequences, I described the Neogene palynomorphs of Hungary (in monographs published in 1958, 1963, 1969, 1985, 1992, and in several papers published in Acta Botanica Hungarica, Pollen et Spores, Grana, etc.). These publications contained known climatic data of supposed recent counterparts of the fossil flora, supplying geologists with palaeoclimatological data. Several of my papers (NAGY 1958, 1967a, 1969, 1970, 1990, 1992a, b) offered a graphical representation and palaeoclimatic interpretation of my data. In association with Lajos Ó. Kovács, computer specialist we developed a graphical method to present climatological (temperature) data of Berhida 3 borehole (Pannonian Pontian) (NAGY and Ó. KOVÁCS 1997). Studies published in several papers by the author and others applied this method. The present study is based on the method outlined there. We attempt a reconstruction of Neogene climate based on major borehole successions of Hungary. This study was supported by Hungarian National Science Foundation grant OTKA T

6 Methods The present interpretation is based on sporomorph studies throughout several decades. Naturally, the quality of data varies, due to various purposes of sampling of borehole profiles (metric subdivision, lithological changes), rarely for palynological purposes. No samples were available for each centimetre of the successions, as is customary for Holocene and Pleistocene profiles. Meeting deadlines often in a rush did not help either. As palynological research is time-consuming and expensive (chemicals, light and electron microscopy, photography), the data are valuable, and their manifold use is imperative. A lifetime of palynological studies is now reviewed, and a revised palaeoclimatological interpretation is offered (NAGY and Ó. KOVÁCS 1997). 6 Figure 1. Outcrop and borehole localities 1. ábra. A vizsgált szelvények, fúrások névadó településeinek térképe

7 Spore and pollen data from selected subsurface profiles and outcrops suitable for palaeoclimatological interpretation were grouped in tropical, subtropical and temperate groups. The place of the settlements nearby the boreholes and outcrops can find see Figure 1. Climatological interpretation is based mostly on WILLIS (1957, 1966) and WALTER and LIETH ( ). For each sample temperature values were calculated according to NAGY and Ó. KOVÁCS (1997), illustrated in plots. The temperature values are thought to be relative, since the calculated values express not the concrete annual mean temperature of the studied period, but indicate only the character of change with time. All taxa were omitted for which no climatological data were available. Beyond temperature the most significant climate data further features were recorded, especially presence of xerophylic forms. Since preservation of sporomorphs is enhanced in humid environments, xerophylic forms are not in situ, but their presence can be assumed not far from the site of embedding. Pteridophytes are significant, being widespread under warmer climates, in the subtropics, rain forests, as I have seen in NE Queensland rain forest and in the subtropical mesophyllous forest in Southern China. ANDREÁNSZKY (1955) and WALTER (1964) considered pteridophytes an important climate indicator. Ecological interrelationships were considered following the principle of actualism. Palaeoeographical knowledge (distribution of land and sea, mountains and plains) helped to solve certain problems. 7

8 Palaeoclimatic interpretation Egerian Early Miocene Egerian formations are relatively small in lateral extent. However, they have direct connections towards the SW, Slovenia and the Transylvanian Basin (HÁMOR et al. 1988; HÁMOR 2001). The Lower Egerian stage of Oligocene age (HÁMOR 2001) is represented by samples from a 80 m borehole in the Wind brickyard and from outcropping Bed x (Figure 2, BÁLDI 1966). Six samples of the underlying Kiscell Clay ( m) contains only nearshore planktonic orgamisms, characteristic for the Oligocene (NAGY 1979). BÁLDI (1966) considered the sequence as of Egerian age from 32.2 m upwards. The following samples were studied: glauconitic, tuffitic sandstone ( m, 2 samples), mollusc clay ( m, 10 samples), outrcopping Bed x (2 samples). Macroflora from the latter is called lower flora by Andreánszky, Legányi and Pálfalvy. Bed x and the underlying Lower Egerian samples are called lower flora here. Upwards there is sterile mollusc sand, overlain by clay. The enclosed macroflora is the so-called middle flora, associated with rich palynoflora, Late Egerian in age. There are no sporomorphs in the overlying 40 m succession of various sandstone and 8 Figure 2. Eger, Wind brickyard profile (outcrop and borehole combined; after BÁLDI 1966) 2. ábra. A Wind téglagyár udvarán létesült fúrás és feltárás szelvénye (BÁLDI 1966 szerint módosítva)

9 Figure 3. The temperature curve of Lower Egerian section. Borehole, Wind brickyard, Eger 3. ábra. Az alsó-egri rétegek hőmérsékleti görbéje, Eger, Wind téglagyári fúrás sand. The next Bed u (with Unio) contains rich macroflora, the upper flora. Samples were taken every 20 cm; 37 samples in total from a m profile (NAGY 1979). Late Egerian is of Miocene age (HÁMOR 2001). The holostratotype profile of the Egerian stage yielded uniform temperature data (Figures 3, 4). Early Egerian temperature ranged from 16.3 to 22.7 C, Late Egerian from 16.9 to 21.9 C. There are more tropical and subtropical than temperate elements. Occasionally tropical elements are dominant. Presence of tropical elements is the largest difference from present-day flora of the Pannonian Basin. Members of Sapotaceae family are most frequent, occurring in 16 of 42 samples (determined after THOMSON and PFLUG 1953), well-known in the Rhein coal deposits since the Palaeocene. WILLIS (1966) mentions Sapotaceae as follows ill-defined genus, 800 species, tropus. Mostly trees. Occurrence: Africa, Malaysia to Pacific, Indochina, SE Asia, Australia, Solomon Islands, W. I., tr. Am.. Heinrich WALTER (1964, p. 105) mentions that Sapotaceae are members of the 60 m tall tree association in the Amazon tropical rain forest. Urania Pflanzenwelt writes: cca. 800 species belong to Sapotaceae, mostly tropical or subtropical with a few exceptions only (DANERT et al. 1976). There is a single species in SW Mexico forming arid Figure 4. The temperature curve of Lower Egerian section. Outcrop, Wind brickyard, Eger 4. ábra. A felső-egri rétegek hőmérsékleti görbéje, Eger, Wind téglagyári feltárás 9

10 forests. Genus Bumelia extends as far to the north as Illinois in the US and as far as Argentina in the south. Sapotacea mostly live in tropical rainforest and savanna (REHDER 1934, p. 732). Sapotaceae is associated with Araliaceae family (WALTER 1964). We found them together in the Lower Egerian sample m, in Bed x, and in Upper Egerian Bed u, Sample 8. Lowest part of rain forest at sea level is formed by palms (WALTER 1964). There are palm pollens (Calamus) in the Lower Egerian profile ( m), Monocolpopollenites tranquillis and Sabalpollenites sp. in the following 3 samples above and in Bed x. There is large amount of Calamus pollen in the upper flora (Bed u, samples 9, 10, 11, 12). Calamus occurs together with other palm pollens at least as single specimens in almost all samples of the succession. Tropical fern spores are mostly from the undergrowth: Cicatricosisporites (Aneimia), Osmunda, Gleichenia, Leiotriletes (Lygodium), Polypodiaceae, Cyathea, Cibotium, Pteridium, Asplenium, and Selaginella. Some of them were possibly epiphytes, as I have seen in the rain forest NE of Brisbane. Pentapollenites (Dodonaea, Sapindaceae) indicates aridity among the tropical Egerian species. Several morphologically distinct species are present. It occurs together with further xerophylic species both in Lower and Upper Egerian samples. Xerophylic species Lower Egerian Upper Egerian Wind brickyard, borehole Wind brickyard, outcrop Dodonaea , , xf, 8, 12 Symplocos 23 Ephedra xa Myrtus xf, 9, 14, 23 Ilex , xa xf, k 7, 9, 32 Artemisia Chenopodiaceae Compositae Symplocos pollen occurs in relatively few samples. It occurs both in the tropics and subtropics in Asia, Australia, Polynesia, and America (WILLIS 1966). Urania Pflanzenwelt mentions (DANERT et al. 1976) green shrub in summer of the Atlantic coast to Delaware, also in North China and Japan. Symplocos occurs in periodically changing, arid, mountain climate. These features indicate that despite many tropical elements does not indicate either rain forest or tropical environment, but warm subtropical climate with an arid season. Pollen of genus Podocarpus is very frequent (in 4 samples of 14 in Lower Egerian, in 10 samples of 16 in Upper Egerian). WILLIS (1964) informs that 100 species of Podocarpus lives from tropical to temperate zones, mostly in the southern hemisphere. Northwards it extends to the Himalayas and Japan. WALTER (1964, p. 203) considers of typical representative of a tropical subalpine forest, together with Dacrydium. There is Podocarpus and Dacrydium together in sample m and in Bed k. Few Engelhardtia pollens occur in both substages of Egerian, in almost all samples. WALTER (1964) mentions Engelhardtia from zones above 1800 m in Java 10

11 ( Regenwälder bei abhähmender Temperatur ), WILLIS (1966) lists it from the Himalayas to Taiwan, in SE Asia, Malaysia, and in Mexico and Central America. Walter found it to grow under 12 to 17 C mean annual tempreature in Java, 3400 mm annual rainfall, and maximum 3 week long arid season. It means that Engelhardtia lives in a tropical region under subtropical conditions. That s why it still occurs in the Pontian stage of the Pannonian Basin. Sporomorphs do not indicate marsh environment in the Eger profile, despite frequent occurrence of Cyrillicae pollen. Taxodiaeceae Cupressaceae forests are represented by few pollen only (note that these plants live outside marshes, too). Myrica and Nyssa the definitive indicators of marsh environment are missing. There are a few definitely subtropical species (extending to the Mediterranean belt, too), which exclude a tropical environment for the Eger profile: Ginkgo, Cedrus, Sciadopitys, and Mediterranean Pinus taeda, Zelkova pollen. Definite temperate species are rare: Alnus pollen is found from Lower Egerian. Upwards there is an increase in temperate genera: Pinus sylvestris-type conifers, Carpinus, Acer, Ostrya species. Warm temperate climate is indicated by Castanea, Juglans, Carya, Pterocarya. Still, tropical and subtropical species dominated over temperate ones during Egerian age. There are frequent quercoid-type pollens, which are not comparable to present-day Quercus (cupuliferoid types of POTONIÉ, THOMSON and THIERGART 1950). Abies and Picea pollen in the Eger profile are considered temperate. These genere occur above 4000 m in the tropics and subtropics. The Eger profile is represents a warm subtropical climate, with 20 C mean annual temperature, cca mm annual rainfall, variable precipitation over the year. There is a short, dry period each year. 19 C mean annual temperature was calculated for the Early, and C for the Late Egerian from holostratotype data. Besides palynological studies (NAGY 1963a, 1979b, 1985, 1992) macroflora was collected, determined and interpreted from Eger (ANDREÁNSZKY 1943a, b, 1955, 1956, 1962, 1966; PÁLFALVY 1961; NAGY and PÁLFALVY 1963; HABLY 1983; KVAČEK and HABLY 1991; HABLY and FERNANDEZ MARON 1998). Andreánszky considered the Eocene as warmest period of the Tertiary. Oligocene has seen dramatic cooling, when southern hemisphere and east Asian subtropical elements increased. Tropical elements are reduced, there are less palms, while Coniferae increase. Upper flora is characterized by tropical elements, increasing broadleaved plants and ferns with increasing precipitation. Turgay elements appear. It might be considered as a result of topographic changes. Palynology offers a similar contradictory picture. Most of tropical ferns: Cicatricosisporites lusaticus, Clavifera, Cibotiides zonatus are in Lower Egerian, and further Cicatricosisporites, Gleichenia species appear in the upper flora. At the same time Coniferae also increase in abundance. Besides subtropical Coniferae (Cedrus, Pinus taeda, Cathaya, Taxodiaceae) there are temperate ones, too (Abies, Picea). Besides Mediterranean broadleaved trees (Myrica, Olea, Zelkova) there are also temperate ones: Acer, Carpinus, Alnus. Warm, subtropical climate ensured the survival of tropical elements, and mountains in the background the existence of temperate vegetation. HABLY (1983) corroborated the presence of temperate elements in the lower flora. 11

12 Andreánszky s opinion is supported by palynology: increase of palms in Late Egerian indicates change in the flora, while mean annual temperature remained the same. Probably dry and wet periods alternated. Dodonaea species are one of the indicators of aridity, indicating relationship not only with the southern hemisphere, but with Northern Africa and Sahara, too (WALTER 1964). Podocarpus is also an element of the southern hemisphere, although extending to SE Asia, too. Presence of xerophylic Saharan Dodonaea species and results of HABLY and FERNANDEZ MARRON (1998) suggests that Early Oligocene southern European subxerophytic species survived into the Egerian in Hungary. Significant amount of Leguminosae (Tricolporopollenites ssp. fallax) supports it. More than half of macroflora species found at Eger (HABLY out of 53, i.e. 56.6%) was recognized in the pollen flora. Lower part of Fót 1 borehole ( m, Szécsény Schlier Formation) is considered as Upper Egerian by Hámor and Halmai. Egerian and overlying Karpatian beds can not be distinguished reliably, neither by foraminifers (GELLAI pers. comm.), nor by palynoflora. Sixty-eight samples yielded a rich flora, containing all characteristic tropical, subtropical and temperate species of the Egerian. Several species represent most genera (possibly due to the large number of samples and better preservation in clay than in the Eger profile). There are much more planktonic organisms (Deflandrea spinulosa, Pleurozonaria manumi, P. minor) indicating neashore, marine environment. Freshwater plankton is identical with Eger. Ferns are represented by very many species. The climatic curve shows temperature ranging from 22.5 C to 13.3 C. Mean annual temperature was 17 C (Figure 5). The curve is relatively straight. Lowest values are more than 3 degrees lower than of the holostratotype, due to an increase in Coniferae, mostly Pinus sylvestris pollen. Not counting them, total number of tropical and subtropical elements is larger than of temperate ones. Abundance of temperate element (pines) might be due to geographic differences. Both localities represent nearshore environment based on marine plankton, but Eger is more proximal to the shore: more sand samples and presence of frequent Calamus Figure 5. The temperature curve of Upper Egerian section, borehole Fót 1 5. ábra. A felső-egri rétegek hőmérsékleti görbéje, Fót 1 fúrás 12 pollen indicating a delta or estuary. Probably Fót was farther from the shore, receiving more windborne Coniferae pollen.

13 Tata TVG 27 borehole is to the west from the other two profiles. Two samples of te 16.5 m profile yielded pollen flora. Pollen spectra indicate typical Upper Egerian flora: Sapotaceae, Dodonaea, Cicatricosisporites sp., Polypodiaceoipollenites gracillimus. Temperature of the Egerian ranged between 15 C and 18 C. Mean annual temperature was 19 C in the Early Egerian (max C, min C). Late Egerian mean was 18 C (max C,min C). Mean annual temperature for the Egerian age in total was C. Eggenburgian Eggenburgian seas were of lesser extent in Hungary than Egerian seas (HÁMOR et al. 1988). Many samples were examined for pollen with meagre results due to infavourable lithology. Eggenburgian transgression progressed from east to west, from the Transylvanian Basin towards Sajó Valley, Ózd, Cserhát, Buda Hills (HÁMOR 1997). Two boreholes, Püspökhatvan 4 and Budajenő 2, dated by marine plankton represent this age. Eggenburgian climate is based on the study of forty samples from to m interval of Püspökhatvan 4 borehole (Szécsény Schlier Formation). The temperature curve (Figure 6) oscillates around 18 C with a mean value of 18.7 C. Highest calculated temperature is 22 C, the lowest is 13.5 C. There are five points higher than 20 C, and two lower than 15 C. There are less tropical species than in the Egerian. There are no Lauraceae, Lobelia, Symplocos, Magnolia, Utricularia, and Calamus. There are no Osmunda, Gleichenia, Cicatricosisporites, and Favoisporites spores. Spores present are Polypodiisporites histiopteroides, P. secundus, P. repandus, P. clatriformis, Polypodiaceoisporites helveticus, P. lusaticus, Corrugatisporites paucivallatus, Dictyophyllidites pessinensis, Punctatisporites crassiexinus, Microfoveolatosporites sellingi. Tropical and subtropical species dominate over temperate ones in all samples. There are very few xerophylic taxa: Ephedra, Chenopodiaceae, Artemisia, Dodonaea in one sample each, Ilex in three samples. Figure 6. The temperature curve of Eggenburgian section, borehole Püspökhatvan 4 6. ábra. Az eggenburgi rétegek hőmérsékleti görbéje, Püspökhatvan 4 fúrás 13

14 Temperature and rainfall distribution was more even than in the Egerian. Probably there was a warm, subtropical climate, where the dry period was longer than the rainy one, while aridity was limited, possibly due to proximity of the sea. There was no strong rainy season either, indicated by low amount of fern spores. Lithology is not favourable for sporpomorph preservation: even large pollen producers like Alnus are represented by a few specimens only. Nine samples of Budajenő 2 borehole ( m) yielded 5 ones suitable for palaeoclimatic interpretation ( m, Mány Formation). Highest temperature is 22.3 C, lowest is 13.4 C. Previously unknown elements appear: Agavaceae, Alangium, Malvaceae. Malvacearumpollis bakonyensis NAGY 1962 described from the Ottnangian of Várpalota 133 borehole is certainly tropical. Its high abundance in the Indian Lower Miocene allowed the establishment of a Malvacearumpollis bakonyensis cenozone (RAO 1995, SAXENA and RAO 1996). RAO (1995) suggested that M. bakonyensis lived near the seashore. Sample m of Budajenő 2 borehole indicates warm, rainy, subtropical seashore environment occupied by a marsh forest. A nearby land was occupied by Ephedra, while mountains in the background supported Ostrya and Juglans, mixed with Coniferae. The terrestrial Zagyvapálfalva Formation overlies the marine succession (HÁMOR 1997). Several boreholes and outcrops were investigated, which yielded no useful palynological data (boreholes Egyházasgerge 1, Nógrádmegyer 1, Nógrádsipek 1, sand pits Nagybátony-Szorospatak, Zagyvapálfalva, Sóshartyán-Korpástető, Kisterenye- Aranyhegy, gravel pit Kazár, Kazár I profile, marine Eggenburgian strata at Ipolytarnóc (NAGY 1992) Tököl 1 borehole found deltaic sediments (Tordas Member of Zagyvapálfalva Formation) with poor and poorly preserved marine plankton, unsuitable for palaeoclimatic analysis. Balaton 26 borehole ( m) is Eggeburgian (Pétervására Sandstone Formation). Five samples from the marine environment of m yielded sporomorphs indicating 19 C mean annual temperature. Terrestrial environments (Pápa 2 borehole in the northern Bakony, Szászvár 2 borehole in Mecsek Mts) are characterized by freshwater algae. Selective fossilization yielded a flora consisting solely very thick walled spores in Pápa 2 borehole all of tropical origin, unsuitable for palaeoclimatic interpretation. Eggenburgian section of Szászvár 8 borehole did not yield useful data. Tekeres 1 borehole ( m, Szászvár Formation) yielded a few sporomorphs, indicating 19.5 C mean annual temperature. For a discussion of stratigraphy see HÁMOR (1997). Twenty-one samples from m section of Lajoskomárom 1 borehole at Mezőföld (eastern Transdanubia) were studied (Budafa Formation). Six of them yielded sporomorphs. Highest mean annual temperature is 19.8 C, lowest 13.2 C. Pleurozonaria digitata occurs in most samples, Micrhystridium sp. in the topmost one, indicating marine environment. Botryococcus braunii occurring with Pleurozonaria indicated freshwater influx. Tropical elements are Sapotaceae, Engelhardtia, Monocolpopollenites tranquillus, Cibotiides zonatus, Leiotriletes maxoides maximus, 14

15 Figure 7. The temperature curve of Eggenburgian section, borehole Lajoskomárom 1 7. ábra. Az eggenburgi rétegek hőmérsékleti görbéje, Lajoskomárom 1 fúrás subtropicals are Tricolporopollenites cingulum pusillus, Taxodiaceae, Myrica, temperate ones are Pinuspollenites labdacus, T. cingulum oviformis, and Alnipollenites verus. Temperature curve is very similar to Püspökhatvan 4 plot (Figure 7). Summarizing data on Eggenburgian climate one can say that there was evenly warm subtropical climate, 18 C mean annual temperature, a relatively long dry season, mm annual precipitation. Ottnangian Extent of Ottnangian sediments is much smaller than of Eggenburgian in Hungary (HÁMOR et al. 1988, HÁMOR 1997). The lower boundary is easily recognized by the lower rhyolite tuff (19.6±1.4 My). Repeated trangression progressed from SE to NE (HÁMOR 1997, 2001), reaching the longitude of Salgótarján only. At the Sajó river the Salgótarján Lignite Formation was deposited in marine, paralic environment, changing towards lacustrine northwestward. At Salgótarján only the uppermost Bed I is paralic (HÁMOR 1997). Terrestrial settings are either limnic or fluviatile. The first palynological study of Salgótarján Lignite Formation was made by SIMONCSICS (1959, 1960). The author s efforts were part of a team Figure 8. The temperature curve of underlayer Eggenburgian section, borehole Kurittyán ábra. A fekü eggenburgi rétegek hőmérsékleti görbéje, Kurittyán 630 fúrás 15

16 Figure 9. The temperature curve of Ottnangian section, Seam V (Feketevölgy, Sajókaza) 9. ábra. Az ottnangi rétegek hőmérsékleti görbéje, Sajókaza, Feketevölgy V. telep studying the Borsod coal region for five years (NAGY and RÁKOSI 1993, BOHN- HAVAS et al. 1998). A composite profile in eastern Borsod Basin suitable for palaeoclimatic interpretation represents the region. Underlying Eggenburgian sediments were hit by Kurittyán 630 borehole ( m). Six samples provided 18.4 C mean annual temperature (Figure 8). The lowermost Seam 5 (Feketevölgy, Sajókaza). Thirty-nine samples were examined from the 4 m thick coal bed. The coal contains clay and sand laminae, top is silicified. Only 28 samples were suitable for interpretation. There are few freshwater plankton (Spirogyra) in samples 9 and 3, where an associated Avicennia indicates mangrove. Dominant marsh forests produced organic matter for coal formation: Taxodiaceae, Myrica, Cyrilla, less Nyssa. This subtropical marsh forest describes climate parameters (Figure 9). Highest mean annual temperature is shown in samples from the bottom of the coal bed: 17.5 C (sample 2), lowest in the middle: 12.5 C (sample 20). Mean temperature averaged from all samples of the coal bed is 15.5 C. There was a wet an a dry season. Dry season has seen leafs of the Taxodiaceae forest fall when xerophylic Ephedra, Dodonaea and palm pollens easily spread into the forest. Calamus, a Figure 10. The temperature curve of Ottnangian section, barren, borehole Tardona ábra. Az ottnangi rétegek hőmérsékleti görbéje, Tardona 30 fúrás meddő 16

17 climbing palm in Taxodiaceae forests occurs. There are few tropical species, low in individuals. Besides the mentioned palms and Dodonaea there are few Sapotaceae, Engelhardtia, Araliaceae, Leguminosae. A few Cycas indicates mountain environment nearby. There is subtropical Ginkgo and Zelkova, too. Temperate Ulmus, Alnus, Carya, Pterocarya, Salix, and quercoid species grew in a lake- or riverside forest with fern undergrowth. Mean annual temperature was 15.9 C with mm precipitation, dry and wet seasons alternating, situated close to the sea. Clastic sediments above the coal of Bed V are represented by five samples of Tardona 30 borehole ( m) (Figure 10). Swamp forest elements (Taxodiaceae, Myrica, Nyssa) disappear, while tropical elements increase. Elements of a mountain forest (Pinaceae, Cedrus) appear, reducing mean temperature values. There are Podocarpaceae, Sapotaceae, single Cycas, Dacrydium and in almost all samples Araliaceae pollen grains, and tropical fern spores. Pollen of southeast Asian plants Ginkgo, Sciadopitys, Liquidambar és Lonicera are present, too. Alternating dry and wet seasons are proven by temperate genera (Salix, Acer, Carya). Mean annual temperature calculated from pollen spectra of the clastics is somewhat higher than of the coal beds: mean 17.2 C maximum 20 C, minimum 13.6 C. Diósgyőr 366 borehole ( m) represents the overburden of Bed V, as shown by a comparison of Figures 10 and 11. Bed IV, 2 m thick, is mined at Lyukóbánya. Fourteen of 20 samples taken were used for interpretation. This bed is less coalified than Bed V, therefore contains more sporomorphs. Tropical elements are identical, while fern spores exceed those in Bed V. Besides a very rich swamp forest elements of mangrove were present. There are traces of marine influence: sample 9 contains marine plankton. Sample 20 contains freshwater Botryococcus braunii, marine plankton, and mangrove pollen. Marine inundation occurred above Sample 2. There are tropical Podocarpus, Engelhardtia, Cycas, elements of a subtropical, temperate mixed forest and gallery forest. Highest temperature calculated for the succession is 17.6 C, lowest is 14.3 C, mean temperature is 15.8 C, somewhat higher than that of Bed V. There are no major excursions in the temperature curve (Figure 12). Figure 11. The temperature curve of Ottnangian section, borehole Diósgyőr ábra. Az ottnangi rétegek hőmérsékleti görbéje, Diósgyőr 366 fúrás 17

18 Figure 12. The temperature curve of Ottnangian section, Seam IV Lyukóbánya 12. ábra. Az ottnangi rétegek hőmérsékleti görbéje, Lyukóbánya IV. telep Figure 13. The temperature curve of Ottnangian section, borehole Tardona ábra. Az ottnangi rétegek hőmérsékleti görbéje, Tardona 72 fúrás Layers between seams III and IV are represented by 10 samples from Tardona 72 borehole ( m). Mean temperature was C, highest value 17.6 C, lowest value 107 C. The temperature curve is more variable than of Seam IV (Figure 13), although it might be due to its greater thickness (129.1 m). There are no samples from Seam III. Layers between Seams III and II are represented by a single sample of Diósgyőr 366 borehole (233.5 m). Temperature was 16.6 C. Seam II is represented by a 1 m thick coal bed in Edelény, shaft IV. There are almost no sporomorphs in the 14 samples taken. The temperature curve is almost linear (Figure 14). Mean temperature based on 3 samples was 15.4 C. Tropical elements are Cycas, Podocarpus, Cyrilla, Polypodiaceoiporites cf. gracillimus. Subtropical swamp forests are represented by Taxodiaceae, Myrica, mountain environment by Podocarpus, Pinus sylvestris típus, Abietinaepollenites microalatus, Cedrus, freshwater open forest by Carya, Ulmus, and Rhus. There are no samples from Seam I. Overburden succession is represented by 5 samples from Diósgyőr 366 borehole ( m). Calculated mean temperature was 14.8 C, with C maximum and 14.2 C minimum (Figure 15). 18

19 Figure 14. The temperature curve of Ottnangian section, Seam II, shaft IV, Edelény 14. ábra. Az ottnangi rétegek hőmérsékleti görbéje, II. telep, Edelény IV. akna Figure 15. The temperature curve of Ottnangian beds, overburden, borehole Diósgyőr ábra. Az ottnangi rétegek hőmérsékleti görbéje, Diósgyőr 366 fúrás, fedő Averages are shown below: Average values: overburden Diósgyőr C Seam II Edelény C barren zone Diósgyőr C Seam III barren zone Tardona C Seam IV Lyukóbánya C barren zone Tardona C Seam V Feketevölgy C underlying bedskurittyán C There is minor decrease of temperature with time, both in the seams and in barren rock. Alsóvadász 1 borehole ( m) is the easternmost studied Ottnangian profile. Eight of eleven samples were suitable for temperature calculations. There is significant amount of tropical taxa. Total of subtropical and tropical elements is always higher than of temperate ones. Frequently forests of coal swamps dominate (Taxodiaexea, Myrica). There are less Sapotaceae and more Engelhardtia than in Borsod in the west. Sporomorph association is rather similar to Seam IV, esp. due to 19

20 the rich fern vegetation. No comparison can be made with Seam V due to its high coal rank. Maximum calculated temperature is 21.6 C, minimum 16.5 C, mean C. There were a few profiles from Mátra and Nógrád region, poor in sporomorphs, unsuitable for numerical analysis. Two samples of Tököl 1 borehole ( m and m) contain Ottnangian sporomorphs. There are marine planktonic organisms, Pleurozonaria concinna, and Hystrichosphaera. The lower sample there are tropical sporomorhs, Sapotaceae, Engelhardtia, Cyrillaceaepollenites megaexactus and fern spores. A very rare form, Myrtaceidites myrtiformis occurs, described by SIMONCSICS (1964) from Katalin Shaft not far away. Mean temperature indicated by the lower sample is 17.6 C, of the upper sample C, mean value is 17.4 C, similar to Ottnangian values gained from elsewhere. Probably there was little or no sedimentation in the Transdanubian Range during Ottnangian; Bántapuszta Formation is Karpatian (HÁMOR 1997). Várpalota 133 borehole ( m) is considered Ottnangian by Kókay. There is no Mecsekisporites, which occurs in the Karpatian. Six of eight samples taken from this 50.7 m thick succession were suitable for numerical analysis. There are many interesting tropical taxa: Malvacearumpollis bakonyensis, Alangiopollis barghoornianum, Acaciapollenites varpalotaënsis, Magnoliaepollenites sp., Monocolpopollenites tranquillus and very much tropical fern. RAO (1995) established a Malvacearumpollis bakonyensis cenozone (Lower Miocene) from an abundant occurrence of this species. There are very few planktonic organisms in the lower samples. A sample from m contains Botryococcus braunii KÜTZ. and Micrhystridium sp. In samples taken from m interval there are Pleurozonaria concinna (COOKS. et MAN.) MÄDL. and Hystrichosphaeridae sp. planktonic organisms, characteristic for nearshore environments. There are even temperature values, never exceeding 18 C, caused by the presence pollen of subtropical and temperate conifers and marsh forests. Highest temperature value attained is 18 C, Figure 16. The temperature curve of Ottnangian section, borehole Várpalota ábra. Az ottnangi rétegek hőmérsékleti görbéje, Várpalota 133 fúrás 20 lowest id 15.9, mean temperature is 16.9 C (Figure 16). Twenty of 26 samples taken from Tekeres 1 borehole ( m)